Color-Changing Slime

Color-Changing Slime


Take standard slime recipes to the next level with thermochromic pigments! These pigments are easy to find online and add an element of color changing magic and mixing to an already exciting slime project. 

 

Liquid starch is commonly used as a laundry and ironing booster. As with any household product, it should be kept away from children not under direct supervision of an adult. Do not allow children to ingest liquid starch. If consumed, contact a poison control center immediately. Wash hands after play.

Ages:
9 - 14
Est. Time:
1-2 hours

How we did it:

Materials List

  1. liquid glue (4 tsp) - We made slime using both white school glue and Elmer's Glitter Glue
  2. water (4 tsp)
  3. liquid starch (4 tsp)
  4. food coloring
  5. glitter - optional
  6. thermochromic pigment
  7. stirring stick - wooden
  8. mixing bowl
  9. hot water (1 glass)
  1. This recipe uses equal parts of water, glue, and liquid starch. For a small batch, we used 4 tsp of each ingredient but feel free to increase the batch for more slime!

     

    Pour the glue and water into the mixing bowl. Stir until it is evenly mixed.


  2. Add a few drops of food coloring to the glue mixture. Note that this will be the color of your slime when it is warm. 

     

    Optional: Sprinkle in glitter to give your slime some sparkle. 


  3. Next, stir in a small amount of thermochromic pigment. This pigment and the food coloring added in step 2 will be the color of your slime when it is room temperature or cold. Make sure that everything is completely mixed.

  4. To make your slime stick together, pour in the liquid starch and slowly stir in circular motions. You will begin to notice the mixture becoming thicker. 

  5. Once the slime becomes a clump in the middle, remove it from the bowl and use your hands to continue to knead the slime. You may need to let it sit in the bowl for a few seconds if it gets too clumpy. Continue to knead the slime for about 5 minutes.

  6. Your slime is now ready to play with! Fill a cup with hot water and press your slime to the outside. What happens to the slime color? Can you make your slime change back? Try dropping your slime into the water! What happens?


    Note: The more you drop your slime in the water the more liquidy it becomes. If it becomes too liquidy, just make a new batch. 

     

    Your slime can be stored in a container or loosely wrapped. When it dries out, it's time to make more slime! 

     

    Experiment with slime by seeing how more or less liquid starch, water, or glue changes the consistency of the slime. You can also use your thermochromic pigment in other recipes to make all types of color changing slime!


  7. What's going on?


    Your slime is made of long molecules of different polymers, including glue and starch, which becomes cross-linked, or intertwined, when you mix them together with water. These cross-linked polymers stick together but can be stretched out and molded into any shape without easily breaking.


    The slime also contains a thermochromic pigment - a pigment that changes its color depending on its temperature (thermochromic comes from the Greek words thermos, which means heat, and chroma, which means color). This particular type of thermochromic pigment is known as a leucodye, and it can only change its color between being transparent and having one color, or between just two colors. The molecules of a leucodye change their shape slightly when heated or cooled, and this shifts the leucodye between its two color states. Leucodyes are also used to make color-changing coffee mugs and t-shirts, because they can easily be printed on a variety of surfaces.